[exporterhelper] move queue metrics to mdatagen

[codeboten]

This uses mdatagen to generate the queue metrics. This will allow users to see the metric in the documentation for exporter helper

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.53%. Comparing base (a2289fd) to head (e2ad6b1).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #10318   +/-   ##
=======================================
  Coverage   92.52%   92.53%           
=======================================
  Files         388      388           
  Lines       18310    18317    +7     
=======================================
+ Hits        16942    16949    +7     
  Misses       1022     1022           
  Partials      346      346           

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